The Age of Sustainable Development" gives students an understanding of the key challenges and pathways to sustainable development - that is, economic development that is also socially inclusive and environmentally sustainable.

Impartido por:

Jeffrey Sachs

Transcripción

[MUSIC] Forests remain one of the major parts of the terrestrial ecosystems on the planet. We know that forests cover something around 30% of the total land area. And we also know that forest cover used to be a far higher proportion of the Earth's land area before humanity got to it. Humanity's been in the business of for thousands and thousands of years of clearing forests. And we read accounts of the massive deforestation in ancient Greece or in the Roman empire, or in ancient China and India thousands of years ago. This is an ancient story. But we continue to lose a lot of rainforest and a lot of other forest areas today, because of the increasing populations and pressures on the planet and the forces of international trade. So what has been going on from ancient times continues and, in some ways, intensifies until today. When we lose forest, [COUGH] we degrade ecosystems. We also lose a tremendous amount of biodiversity. Our rainforest areas, the three great rainforest areas of the Amazon basin, the Congo basin and the Indonesian archipelago are home to countless species and much of the greatest biodiversity on the planet. And as those rainforests are being depleted right now, are threat of massive deforestation and degradation. We are also losing huge amounts of biodiversity as well. This map gives us a suggestion of the extent of past deforestation and some of the challenges of current deforestation. Every area shaded in this map is an area that originally had forest cover. The very light shaded areas, say in Western Europe or across China or across Russia and the Eurasian land mass. The light shaded areas in the eastern half of the United States [COUGH] are areas that were original forest cover that have been deforested. So western Europe, much of the eastern, half of the United States essentially all of China, lost its original forest cover to human activity. The case of China, hundreds of years ago that process was already complete. India as well, having lost a huge amount of its original forest cover. Europe, having lost a huge amount of its original forest cover, hundreds and in some cases thousands of years ago. Today, most deforestation [COUGH] is taking place in the fast growing tropical and subtropical regions and notably in the rain forest where population densities were low traditionally. But had been rising and where these rainforest regions are increasingly being encroach for human provisioning for tropical log woods or for clearing for farm land and for pasture land. Or for provisioning of peasant small holders who go into the forest for fuel wood or for bush meat or for other needs of people living on the margins of the forests. And the result is while temprid zone areas were deforested in historical time, it's now the tropical areas that are under the most direct force of deforestation today. Not because there's something intrinsic about tropical deforestation but rather, in a way from a historical point of view because it's coming last in line. It's a set of ecosystems that were relatively less disturbed previously but now are facing major disturbances and human impacts. Some of that human impact is internally driven by growing populations within countries, within Brazil, or within Central Africa, for example, or in Southeast Asia. But a huge amount I'm going to want to draw our attention to, is coming from international trade. From demands halfway around the world for these forest products. And this is very, very difficult to control because it means high levels of demand often from rich countries or rapidly growing economies, like China, even overwhelm local protective services. It's easier to bribe. It's easy to engage in illegal activities even when they are on the books under legal control. This map that you're looking at now shows us the current patterns of deforestation. It emphasizes that in Areas that were traditionally deforested say, the eastern part of the United States or western Europe or northern Europe. There is some reforestation taking place in those areas, that's a very healthy point. But the red areas shown on this map are areas that the millennium ecosystem assessment identified as being areas. Under a current intensive process of deforestation and that includes parts of the tropical rain forests I've mentioned. Large regions in Southeast Asia, of course the Andean region as well. Many parts of the world, where there are remaining forests find those forests under threat. Forests are major providers and regulators of ecosystem services. And this means that the threats to these forests are threats to human well being. And it's worth listening to the words of one of the great scientist of our age James Lovelock, who is the creator of the Gaia Theory which is basically the theory of the interconnectedness of the world's ecosystems and the interconnected regulatory processes of those ecosystems. Lovelock, more than most or scientists 30, 40, 50 years ago, emphasize the interconnectedness of the climate regulatory functions and other natural flux functions of energy, heat dissipation, nutrient flows and so forth, played by ecosystems. Emphasizing that when we degrade one ecosystem, we impede,or undermine the functioning of ecosystems in other parts of the planet. So, here is what Lovelock says, for example about the deforestation of the tropical rainforests. He says and I'm quoting, no longer do we have to justify the existence of humid tropical forests on the feeble grounds that they might carry plans with drugs that cure human disease. Because he's saying that was one argument that conservationists were emphasizing. Maybe the main one. Don't cut down the rainforest. There may be a life saving medicine there. There's truth to that, but what Lovelock is saying is that's not the only truth. Gaia theory forces us to see that they offer much more than this. Through their capacity to evapotranspirate vast volumes of water vapor, they serve to keep the planet cool by wearing a sunshade of white reflecting cloud. So the rainforests have cloud cover above it. A lot of that cloud cover reflects the incoming ultraviolet radiation, sending it out into space, rather than having it hit the Earth, warm the Earth, reradiate as infrared. And so, the changing reflectance of the planet caused by the existence of the rainforests is a regulatory feature of climate. Not intuitive, not of our every day nature, but recognized by an interconnected Earth systems science. So, Lovelock concludes their replacement by cropland could precipitate a disaster that is global in scale. The point, is that when we degrade large ecosystems, such as tropical ecosystems, the impacts can be far more than we would recognize in the absolute direct impact of the loss of the local ecosystem services. Earth systems science teaches us that the interaction of the ecosystems in their global regulation of climate, water cycle, other nutrient cycle, nitrogen fluxes are also of huge significance for planetary balances and for human well-being. Well, the extent of degradation is enormous, the pressures are vast and the pressures are coming from many different directions. Have a look at the island of Borneo which is shared in the present day by Malaysia and Indonesia. Malaysia, with its two states of Saba and Sarawak and Indonesia, with the state of Kalimantan. This island is absolutely under the most incredibly rapid and deep transformation because one of the most diverse wondrous ecosystems of forest area is essentially being cut down and replaced by a monoculture for palm oil production. Palm oil is in huge demand. Since palm oil is a very versatile product it commands a good market price. It's used in many home products, it's used in cooking and for home use and It's sold in demand in recent decades. And the maps that you're looking at, produced by UNEP, both show the actual decline of forest cover on the island of Borneo up through the year 2005. And then, projections that were made under a business-as-usual trajectory for 2010 and 2020. What you're observing here essentially is deforestation to replace a highly biodiverse rainforest area with a monoculture of palm oil. Palm oil in limited production is okay. And when it's carefully monitored and measured and kept within certain boundaries, it can make sense. But it sweeps the island of Borneo and as is similarly taking place in Sumatra in Indonesia. If you get a massive replacement of the diverse ecosystem with a monoculture the losses will be phenomenal. The losses to regulatory functions of these ecosystems. The losses to biodiversity in the specific context of Indonesia Malaysia. Huge threats to the loss of, again, one of our closest, great ape relatives, the orangutan, whose habitat is, precisely in this rain forest areas whose numbers have declined and whose habitat is under a tremendous threat. And in last we take into account what is a sustainable harvesting of tropical forests. What is in the same way, that we need to take into account the sustainable harvesting of fisheries and other ecosystems? We will, before we know it, have lost these ecosystems. They will have fallen into an irreversible Collapse. There's an attempt to do something about it of course, in fact there are several attempts. One that is notable is to link the conservation of the rain forests and forests in general with the climate change agenda. Because remember that perhaps 15% of the total carbon dioxide emissions each year are coming from land use change, especially from deforestation. And so the idea was taken several years ago that as part of the mitigation efforts. Not only should we be reducing our carbon footprint in the energy sphere, but also the carbon emissions coming from deforestation. And the project that has grown up from that is called REDD+, R E D D+ which stands for Reduced Emissions from Deforestation and forest Degradation. And so it's both the thinning of forests and the clearing of forests that are the target of the REDD+ initiative. The idea, and it's a good one, is to give financial incentives to farmers and to communities and to forest communities in general, often including indigenous populations to protect the forests and to replace part of the income that in the short term, they would lose from their over exploitation of the forest products, with a sustainable flow of income of other kinds, including a top up of income being provided by donor countries. Norway for example has offered a billion dollars to Brasil. In a REDD+ initiative to slow or stop the deforestation of the Amazon and to use this funding to create financial incentives for forced communities in the Amazon, to play the role of protecting the Amazon rather than facilitating its loss. The map that you're seeing here are the participating countries. The countries in red are countries that are actively receiving from the United Nations support for developing red plus programs. Other partner countries are shown in blue. It is an important effort. The funding by some countries like Norway's been extremely generous. But it's still a small counter pressure to an overwhelming force coming from the global marketplace. For the products either directly of the forests themselves or for the products that are grown, the meat products, or the soy beans or others that are grown when the, and palm oil, when the forests are cleared and replaced by other kinds of economic activity. Let's look in more depth at programs like REDD+ to see what the international response is to the loss of biodiversity. To see how that response is functioning to date, and to make a kind of assessment of how we might and need to strengthen that response if we are to reverse the very powerful wave of species extinction and ecosystem loss that now was engulfing so much of the planet. [MUSIC]